Exhaust Flue Module Isolation for Low-Frequency Ship Vibrations
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Solution Overview
Problem
Cruise ships face challenges in reducing vibrations and noise from exhaust flue components, such as SCR systems, exhaust gas boilers, and silencers, which are not effectively mitigated by current elastic suspensions, especially in low-frequency ranges, leading to structural noise transmission to adjacent habitable areas.
Innovation Solution
The ship is designed with a system that divides the exhaust flue components into structurally independent modules supported by main and secondary platforms, using high-efficiency, low-frequency elastic suspensions to isolate low-frequency vibrations, allowing the natural frequency of the system to be lowered and decoupled from engine operation frequencies, thereby reducing vibration transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional elastic suspensions are used to support exhaust flue components, then some vibration isolation is achieved, but low-frequency vibrations are not effectively mitigated and continue to transmit to the casing structure
Solution Approach 1:
The exhaust flue system is divided into multiple independent modules (SCR module, boiler module, silencer module, etc.), each supported by its own elastic suspension system. This segmentation allows each module to be isolated independently, preventing vibration transmission paths and enabling targeted vibration control for low-frequency vibrations that traditional single-point suspensions cannot effectively mitigate.
Solution Approach 2:
Elastic suspension elements are introduced as intermediary components between the exhaust flue modules and the casing structure. These suspensions act as vibration isolators that specifically target low-frequency vibrations, absorbing and dampening them before they can transmit to the casing and habitable areas, thereby resolving the contradiction between maintaining support function and blocking vibration transmission.
2Object-affected harmful factors
If buffer spaces are added around the casing to reduce vibrations, then vibration isolation improves, but valuable onboard space is lost
Solution Approach 1:
The vibration isolation function is extracted from the spatial buffer approach and integrated directly into the exhaust flue module supports. By incorporating elastic suspension elements at the module level, the patent achieves vibration isolation without requiring additional buffer spaces around the casing, thus preserving valuable onboard space while effectively reducing vibration transmission to habitable areas.
3Strength
If exhaust flue components are rigidly supported to ensure structural stability, then structural strength is maintained, but vibration and noise transmission to the casing increases
Solution Approach 1:
The support system employs different local qualities: rigid connections within each exhaust flue module to maintain structural integrity, and elastic suspension elements at the module-casing interfaces to isolate vibrations. This combination allows the structure to maintain strength where needed while blocking vibration transmission paths to the casing and habitable areas.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces low-frequency and ultra-low-frequency vibrations to the ship's structure without the need for buffer spaces, preserving valuable onboard space and maintaining similar production costs to traditional solutions.
Implementation Method 1
The main elastic suspensions (61) of each main platform (51) are sized to exploit the total mass of the respective module (50a-e) in order to cut the transmission of low-frequency vibrations
Implementation Method 2
main elastic suspensions (61) of each main platform (51)
Data Source
AI summary
The invention relates to a ship, comprising: at least one casing that delimits a cavity extending vertically across the ship's decks; at least one exhaust flue that is installed inside said casing and comprises a plurality of concentrated mass components and a plurality of components with mass distributed in length; a plurality of structures that support the plurality of said components inside the casing. Said support structures comprise: a plurality of main platforms, which define a main support base inside said cavity and is connected to walls of the casing at a ship deck by means of the interposition of main elastic suspensions; and a plurality of secondary platforms, which are directly or indirectly supported only by one of said main platforms and defines a secondary support base arranged at a different height with respect to the main support base that is defined by the corresponding main platform.